Does it always have to be "the match"? Why not to say "The game is scheduled for Saturday?"

It can be a game, but if you’re talking about certain sports like soccer or tennis, it’s normally called a match.

I've heard "soccer game" many times. "Game" seems be more general embracing many sports. In this case, I guess, we could use both.

A game is a game, but a match is a planned competitive event, like a championship or a match-up between two rival teams.